Field
The present disclosure relates generally to apparatus and methods for low power sensing of wireless access technologies, and more specifically to sensing or searching for various wireless access technologies or radio access technologies (RATs) using a low power means in a mobile device operable for detecting and/or acquiring a signal from one or more of the various RATs and communicating detection to other higher power domains in the mobile device.
Background
In certain wireless devices, such as mobile communication devices, it is desirable to utilize battery energy efficiently in order to provide long service between recharges. In particular wireless devices at least a portion of the circuitry within the devices can be turned on for short periods of time when the device is actively receiving or transmitting, and at least some of the energy consuming circuitry turned off during idle periods or sleep cycles. It is desirable to minimize the time that such devices are turned on in order to maximize energy savings.
Additionally, it is known to provide user equipment (UE), access terminals (ATs), or other mobile devices that utilize various radio area technologies (RATs), such as wireless wide area network (WWAN) technologies (e.g., WCDMA, WiMAX, UMB, CDMA200, IS-95, LTE, etc.). Dependent on the current state of network service available to a mobile device in a particular location, for those RATs not available, powering up of active circuitry to receive and transmit using these networks is unnecessary. Such known techniques thus lead to unnecessary power usage by powering up active or primary circuitry for detection of particular RATs that are not present. Accordingly, when a mobile communication device is out of a service area for a particular RAT, it may be desirable to shut down portions of circuitry in the device that are not required for such RATs in order to save energy. However, as network conditions or mobile location changes, it is also desirable to periodically check or sense whether a particular RAT is currently available thus requiring power up of primary circuitry in known systems. Accordingly, lower power sensing of various RATs by a mobile device that saves energy over the use of active or primary circuitry for sensing, particularly in those instances where certain RATs are not available, would be desirable.